Effect of different dispersing agents on the characteristics of Eudragit microspheres prepared by a solvent evaporation method

Impact of porous microsponges in minimizing myotoxic side effects of simvastatin

Simvastatin (SV) is a poorly soluble drug; its oral administration is associated with a significant problem: Myopathy. The present study aims to formulate SV microsponges that have the potential to minimize the myotoxicity accompanying the oral administration of the drug. SV microsponges were prepared by exploiting the emulsion solvent evaporation technique. The % entrapment efficiency (%EE) of the drug approached 82.54 ± 1.27%, the mean particle size of SV microsponges ranged from 53.80 ± 6.35 to 86.03 ± 4.79 µm in diameter, and the % cumulative drug release (%CDR) of SV from microsponges was significantly higher than that from free drug dispersion much more, the specific surface area of the optimized microsponges formulation was found to be 16.6 m²/g revealed the porosity of prepared microsponges. Histological and glycogen histochemical studies in the skeletal muscles of male albino rats revealed that microsponges were safer than free SV in minimizing myotoxicity. These findings were proven by Gene expression of Mitochondrial fusion and fission (Mfn1) & (Fis1) and (Peroxisome proliferator-activated receptor gamma co-activator 1α) PGC-1α. Finally, our study ascertained that SV microsponges significantly decreased the myotoxicity of SV.

Development andin-vitroevaluation of modified release tablets including ethylcellulose microspheres loaded with diltiazem hydrochloride

In this study, development of modified release tablet formulations containing diltiazem hydrochloride-loaded microspheres to be taken once rather than two or three times a day was attempted. For this purpose, ethylcellulose microspheres were prepared by emulsion-solvent evaporation technique. The influence of emulsifier type and drug/polymer ratio on production yield, encapsulation efficiency, particle size, surface morphology and in-vitro release characteristics of the microspheres was evaluated. Suitable microspheres were selected and tabletted using different tabletting agents, Ludipress, Cellactose80, Flow-Lac100 and excipients Compritol888 ATO, KollidonSR. Tablets were evaluated from the perspective of physical and in-vitro drug release characteristics. It was seen that type and ratio of the excipients played an important role in the tabletting of the microspheres. As a result, two tablet formulations containing 180 mg diltiazem hydrochloride and using either Compritol888 ATO or KollidonSR were designed successfully and maintained drug release for 24 h with zero order and Higuchi kinetics, respectively.

Influence of aluminum tristearate and sucrose stearate as the dispersing agents on physical properties and release characteristics of eudragit RS microspheres

The purpose of this research was to investigate the effects of different concentrations of polymer and sucrose stearate, aluminum tristearate as dispersing agents on microsphere properties and performance. The yield values of microspheres were over the 78%, and the encapsulation efficiencies were found to be approximately 73%. Particle sizes of microspheres prepared with aluminum tristearate were between 76 and 448 microm, while that of the microspheres containing sucrose stearate were between 521 and 2000 microm. Morphological and physicochemical properties of microspheres were investigated by scanning electron micrography and differential scanning calorimetry (DSC). DSC analysis indicated that verapamil hydrochloride formed a solid solution with acrylic polymers. In vitro release studies were performed using the flow-through cell method. While approximately 80% of drug was released from the microspheres containing aluminum tristearate in 480 minutes, the same amount of drug was released from microspheres containing sucrose stearate in only 60 minutes. Chemical structures and concentrations of the dispersing agents were clearly effective on the physical properties of microspheres and their drug-release characteristics.